E-cigarettes likely represent a lower risk to health than traditional combustion cigarettes, but they are not innocuous. Recently reported emission rates of potentially harmful compounds were used to assess intake and predict health impacts for vapers and bystanders exposed passively. Vapers’ toxicant intake was calculated for scenarios in which different e-liquids were used with various vaporizers, battery power settings and vaping regimes. For a high rate of 250 puff day–1 using a typical vaping regime and popular tank devices with battery voltages from 3.8 to 4.8 V, users were predicted to inhale formaldehyde (up to 49 mg day–1), acrolein (up to 10 mg day–1) and diacetyl (up to 0.5 mg day–1), at levels that exceeded U.S. occupational limits. Formaldehyde intake from 100 daily puffs was higher than the amount inhaled by a smoker consuming 10 conventional cigarettes per day. Secondhand exposures were predicted for two typical indoor scenarios: a home and a bar. Contributions from vaping to air pollutant concentrations in the home did not exceed the California OEHHA 8-h reference exposure levels (RELs), except when a high emitting device was used at 4.8 V. In that extreme scenario, the contributions from vaping amounted to as much as 12 μg m–3 formaldehyde and 2.6 μg m–3 acrolein. Pollutant concentrations in bars were modeled using indoor volumes, air exchange rates and the number of hourly users reported in the literature for U.S. bars in which smoking was allowed. Predicted contributions to indoor air levels were higher than those in the residential scenario. Formaldehyde (on average 135 μg m–3) and acrolein (28 μg m–3) exceeded the acute 1-h exposure REL for the highest emitting vaporizer/voltage combination. Predictions for these compounds also exceeded the 8-h REL in several bars when less intense vaping conditions were considered. Benzene concentrations in a few bars approached the 8-h REL, and diacetyl levels were close to the lower limit for occupational exposures. The integrated health damage from passive vaping was derived by computing disability-adjusted life years (DALYs) lost due to exposure to secondhand vapor. Acrolein was the dominant contributor to the aggregate harm. DALYs for the various device/voltage combinations were lower than—or comparable to—those estimated for exposures to secondhand and thirdhand tobacco smoke.

Use of electronic cigarettes has grown exponentially over the past few years, raising concerns about harmful emissions. This study quantified potentially toxic compounds in the vapor and identified key parameters affecting emissions. Six principal constituents in three different refill “e-liquids” were propylene glycol (PG), glycerin, nicotine, ethanol, acetol, and propylene oxide. The latter, with mass concentrations of 0.4–0.6%, is a possible carcinogen and respiratory irritant. Aerosols generated with vaporizers contained up to 31 compounds, including nicotine, nicotyrine, formaldehyde, acetaldehyde, glycidol, acrolein, acetol, and diacetyl. Glycidol is a probable carcinogen not previously identified in the vapor, and acrolein is a powerful irritant. Emission rates ranged from tens to thousands of nanograms of toxicants per milligram of e-liquid vaporized, and they were significantly higher for a single-coil vs a double-coil vaporizer (by up to an order of magnitude for aldehydes). By increasing the voltage applied to a single-coil device from 3.3 to 4.8 V, the mass of e-liquid consumed doubled from 3.7 to 7.5 mg puff–1 and the total aldehyde emission rates tripled from 53 to 165 μg puff–1, with acrolein rates growing by a factor of 10. Aldehyde emissions increased by more than 60% after the device was reused several times, likely due to the buildup of polymerization byproducts that degraded upon heating. These findings suggest that thermal degradation byproducts are formed during vapor generation. Glycidol and acrolein were primarily produced by glycerin degradation. Acetol and 2-propen-1-ol were produced mostly from PG, while other compounds (e.g., formaldehyde) originated from both. Because emissions originate from reaction of the most common e-liquid constituents (solvents), harmful emissions are expected to be ubiquitous when e-cigarette vapor is present.

Ventilation rates (VRs) in buildings must adequately control indoor levels of pollutants; however, VRs are constrained by the energy costs. Experiments in a simulated office assessed the effects of VR per occupant on perceived air quality (PAQ), Sick Building Syndrome (SBS) symptoms, and decision-making performance. A parallel set of experiments assessed the effects of VR per unit floor area on the same outcomes. Sixteen blinded healthy young adult subjects participated in each study. Each exposure lasted four hours and each subject experienced two conditions in a within-subject study design. The order of presentation of test conditions, day of testing, and gender were balanced. Temperature, relative humidity, VRs, and concentrations of pollutants were monitored. Online surveys assessed PAQ and SBS symptoms and a validated computer-based tool measured decision-making performance. Neither changing the VR per person nor changing the VR per floor area, had consistent statistically significant effects on PAQ or SBS symptoms. However, reductions in either occupant-based VR or floor-area-based VR had a significant and independent negative impact on most decision-making measures. These results indicate that the changes in VR employed in the study influence performance of healthy young adults even when PAQ and SBS symptoms are unaffected.

This study was conducted to assess the current impact of natural gas appliances on air quality in California homes. Data were collected via telephone interviews and measurements inside and outside of 352 homes. Passive samplers measured time-resolved CO and time-integrated NOX, NO2, formaldehyde, and acetaldehyde over ~6-day periods in November 2011 – April 2012 and October 2012 – March 2013. The fraction of indoor NOX and NO2 attributable to indoor sources was estimated. NOX, NO2, and highest 1-h CO were higher in homes that cooked with gas and increased with amount of gas cooking. NOX and NO2 were higher in homes with cooktop pilot burners, relative to gas cooking without pilots. Homes with a pilot burner on a floor or wall furnace had higher kitchen and bedroom NOX and NO2compared to homes without a furnace pilot. When scaled to account for varying home size and mixing volume, indoor-attributed bedroom and kitchen NOX and kitchen NO2 were not higher in homes with wall or floor furnace pilot burners, although bedroom NO2 was higher. In homes that cooked 4 h or more with gas, self-reported use of kitchen exhaust was associated with lower NOX, NO2, and highest 1-h CO. Gas appliances were not associated with higher concentrations of formaldehyde or acetaldehyde.

Measurements were taken in new US residences to assess the extent to which ventilation and source control can mitigate formaldehyde exposure. Increasingventilation consistently lowered indoor formaldehyde concentrations. However, at a reference air exchange rate of 0.35 h-1, increasing ventilation was up to 60% less effective than would be predicted if the emission rate were constant. This is consistent with formaldehyde emission rates decreasing as air concentrations increase, as observed in chamber studies. In contrast, measurements suggest acetaldehyde emission was independent of ventilation rate. To evaluate the effectiveness of source control, formaldehyde concentrations were measured in Leadership in Energy and Environmental Design (LEED) certified/Indoor airPLUS homes constructed with materials certified to have low emission rates of volatile organic compounds (VOC). At a reference air exchange rate of 0.35 h-1, and adjusting for home age, temperature and relative humidity, formaldehyde concentrations in homes built with low-VOC materials were 42% lower on average than in reference new homes with conventional building materials. Without adjustment, concentrations were 27% lower in the low-VOC homes. The mean and standard deviation of formaldehyde concentration were 33 µg m-3 and 22 µg m-3 for low-VOC homes and 45 µg m-3 and 30 µ g m-3 for conventional.

Ventilation standards for commercial buildings set a minimum required outdoor air ventilation rate per occupant to control indoor levels of pollutants including bioeffluents from occupants and their activities and/or a minimum ventilation rate per unit floor area to control indoor levels of pollutants from the building and products used in the building. However, few data are available to indicate the relative importance of controlling occupant-related or building-generated pollutants with ventilation. An experimental facility was designed that allows the independent control of ventilation per occupant and ventilation per floor area in a simulated office environment. Two studies were conducted to measure the impact of either occupant or floor-area based ventilation separately. Thirty-two subjects were assigned to groups of four and each group experienced two different blinded ventilation scenarios in different sequences, with four groups participating in each study. Each test condition lasted four hours and each group experienced two conditions per day in a self-paired study design. The order of presentation of test conditions, day of testing and gender were balanced. Temperature, relative humidity and airflow rates were controlled and logged continuously. Particle number concentrations, size resolved particle mass concentrations, CO2 and ozone were logged continuously. Short-term integrated measurements of volatile organic compounds were collected during each session. The subjects were surveyed using on-line instruments to assess perceived air quality (PAQ), sick building syndrome (SBS) symptoms and decision-making performance. The resulting data were analyzed using statistical models. Neither changing the ventilation rate per person nor changing the ventilation rate per floor area, in the range and for the duration tested here, had consistent statistically significant effects on PAQ or SBS symptoms. However, moderate reductions in either occupant-based ventilation rate or floor-area based ventilation rate had a significant and independent negative impact on a range of decision-making measures. These results provide compelling evidence that changes in outdoor air ventilation rate influences human performance even when PAQ and SBS symptoms are unaffected. The results for occupant-based ventilation agree with previous work that measured the relationship between CO2concentration and decision-making performance in an office setting, with CO2 levels modified by injection of pure CO2. The results for area-based ventilation represent the first controlled human study showing a statistically significant reduction in decision-making performance as a function of decreased ventilation rate per unit floor area of office space. Further study should focus on quantifying the influence of outdoor air on cognitive function across a wider range of ventilation settings to identify the optimal ventilation rate for occupancy and for floor area

Sixteen apartments serving low-income populations in three buildings were retroﬁt with the goal of simultaneously reducing energy consumption and improving indoor environmental quality (IEQ). Retroﬁt measures varied among apartments and included, among others, envelope sealing, installation of continuous mechanical ventilation systems, upgrading bathroom fans and range hoods, attic insulation, replacement of heating and cooling systems, and adding wall-mounted particle air cleaners. IEQ parameters were measured, generally for two one-week periods before and after the retrofits. The measurements indicate an overall improvement in IEQ conditions after the retrofits. Comfort conditions, bathroom humidity, and concentrations of carbon dioxide, acetaldehyde, volatile organic compounds, and particles generally improved. Formaldehyde and nitrogen dioxide levels decreased in the building with the highest concentrations, were unchanged in a second building, and increased in a third building. IEQ parameters other than particles improved more in apartments with continuous mechanical ventilation systems installed. In general, but not consistently, larger percent increases in air exchange rates were associated with larger percent decreases in indoor levels of the pollutants that primarily come from indoor sources.

Present home energy retrofit programs do not account for the effect of retrofits on indoor environmental quality conditions that influence comfort and health. This project developed a systematic procedure for selecting packages of retrofits that have the potential to simultaneously save energy and improve indoor environmental conditions in apartments. The procedure was used to select retrofits for 16 apartments and the resulting changes in indoor environmental conditions and apartment energy use were assessed. Implementation of the retrofits resulted in overall, but not universal, improvements in indoor environmental quality conditions. Ideally, the project would have provided unambiguous evidence of simultaneous energy savings. However, based on the large year-to-year changes in energy use in non-retrofit control apartments, the study was too small for accurate measurement of energy savings. Communication of study methods and results to utilities, policy makers, and owners and managers of subsidized multifamily housing has raised awareness of the opportunity to simultaneously save energy and improve comfort and indoor air quality when apartments are retrofit.

This study investigated formaldehyde and acetaldehyde passive sampling rates and ozone interference for the DNPH-based Waters Sep-Pak XPoSure sampler. Previous studies have shown that ozone interferes with active sampling by this cartridge. Our study included one laboratory and six field experiments conducted in Northern California homes. Passive sampling rates of 1.10 ± 0.09 and 0.86 ± 0.10 mL/min determined for formaldehyde and acetaldehyde are lower than previously reported. In a controlled laboratory experiment there were small, statistically insignificant impacts of subsequent ozone exposure on formaldehyde and acetaldehyde mass passively collected on the samplers. This sampler is inexpensive, easy to deploy and to transport by mail, and has a high sampling capacity when used passively; it is suitable for a wide-range of monitoring applications. However, the passive sampling rate remains in question given the internally consistent, but different results obtained in our study and the previous study.

Diffusive or passive sampling methods using commercially filled axial-sampling thermal desorption tubes are widely used for measuring volatile organic compounds (VOCs) in air. The passive sampling method provides a robust, cost effective way to measure air quality with time-averaged concentrations spanning up to a week or more. Sampling rates for VOCs can be calculated using tube geometry and Fick’s Law for ideal diffusion behavior or measured experimentally. There is evidence that uptake rates deviate from ideal and may not be constant over time. Therefore, experimentally measured sampling rates are preferred. In this project, a calibration chamber with a continuous stirred tank reactor design and constant VOC source was combined with active sampling to generate a controlled dynamic calibration environment for passive samplers. The chamber air was augmented with a continuous source of 45 VOCs ranging from pentane to diethyl phthalate representing a variety of chemical classes and physiochemical properties. Both passive and active samples were collected on commercially filled Tenax TA thermal desorption tubes over an 11-day period and used to calculate passive sampling rates. A second experiment was designed to determine the impact of ozone on passive sampling by using the calibration chamber to passively load five terpenes on a set of Tenax tubes and then exposing the tubes to different ozone environments with and without ozone scrubbers attached to the tube inlet. During the sampling rate experiment, the measured diffusive uptake was constant for up to seven days for most of the VOCs tested but deviated from linearity for some of the more volatile compounds between seven and eleven days. In the ozone experiment, both exposed and unexposed tubes showed a similar decline in terpene mass over time indicating back diffusion when uncapped tubes were transferred to a clean environment but there was no indication of significant loss by ozone reaction.

10aindoor air quality10aPassive Sampling10aUptake Rates10avocs1 aMaddalena, Randy, L.1 aParra, Amanda1 aRussell, Marion, L.1 aLee, Wen-Yee uhttps://indoor.lbl.gov/publications/measurement-passive-uptake-rates02048nas a2200205 4500008003900000245013500039210006900174520133400243653001701577653001601594653001601610653000901626100001801635700001901653700002201672700002401694700002501718700002201743856007701765 2013 d00aVentilation Control of Volatile Organic Compounds in New U.S. Homes: Results of a Controlled Field Study in Nine Residential Units0 aVentilation Control of Volatile Organic Compounds in New US Home3 a

In order to optimize strategies to remove airborne contaminants in residences, it is necessary to determine how contaminant concentrations respond to changes in the air exchange rate. The impact of air exchange rate on the indoor concentrations of 39 target volatile organic compounds (VOCs) was assessed by measuring air exchange rates and VOC concentrations at three ventilation settings in nine residences. Active sampling methods were used for VOC concentration measurements, and passive perfluorocarbon tracer gas emitters with active sampling were used to determine the overall air exchange rate corresponding to the VOC measurements at each ventilation setting. The concentration levels and emission rates of the target VOCs varied by as much as two orders of magnitude across sites. Aldehyde and terpene compounds were typically the chemical classes with highest concentrations, followed by alkanes, aromatics, and siloxanes. For each home, VOC concentrations tended to decrease as the air exchange rate was increased, however, measurement uncertainty was significant. The indoor concentration was inversely proportional to air exchange rate for most compounds. For a subset of compounds including formaldehyde, however, the indoor concentration exhibited a non-linear dependence on the timescale for air exchange.

Sixteen previously occupied temporary housing units (THUs) were studied to assess emissions of volatile organic compounds. The whole trailer emission factors were evaluated for 36 VOCs including formaldehyde. Indoor sampling was carried out in theTHUs located in Purvis staging yard in Mississippi, USA. Indoor temperature and relative humidity (RH) were also measured in all the trailers during sampling. Indoor temperatures were varied (increased or decreased) in a selection of THUs using theheating, ventilation and air conditioning (HVAC) systems. Indoor temperatures during sampling ranged from 14º C to 33º C, and relative humidity (RH) varied between 35% and 74%. Ventilation rates were increased in some trailers using bathroom fans andvents during some of the sampling events. Ventilation rates measured during some a selection of sampling events varied from 0.14 to 4.3 h-1. Steady state indoor formaldehyde concentrations ranged from 10 μg-m-3 to 1000 μg-m-3. The formaldehyde concentrations in the trailers were of toxicological significance. The effects of temperature, humidity and ventilation rates were also studied. A linear regression model was built using log of percentage relative humidity, inverse of temperature (in K-1), and inverse log ACH as continuous independent variables, trailermanufacturer as a categorical independent variable, and log of the chemical emission factors as the dependent variable. The coefficients of inverse temperature, log relative humidity, log inverse ACH with log emission factor were found to be statistically significant for all the samples at the 95% confidence level. The regression model was found to explain about 84% of the variation in the dependent variable. Most VOC concentrations measured indoors in the Purvis THUs were mostly found to be below values reported in earlier studies by Maddalena et al.,1,2 Hodgson et al.,3 and Hippelein4. Emissions of TMPB-DIB (a plasticizer found in vinyl products) were found to be higherthan values reported in comparable housing by Hodgson et al.,3. Emissions of phenol were also found to be slightly higher than values reported in earlier studies1,2,3. This study can assist in retrospective formaldehyde exposure assessments of THUs whereestimates of the occupants indoor formaldehyde exposures are needed.

The developers of the Paharpur Business Center (PBC) and Software Technology Incubator Park in New Delhi, India offer an environmentally sustainable building with a strong emphasis on energy conservation, waste minimization and superior indoor air quality (IAQ). To achieve the IAQ goal, the building utilizes a series of air cleaning technologies for treating the air entering the building. These technologies include an initial water wash followed by ultraviolet light treatment and biolfiltration using a greenhouse located on the roof and numerous plants distributed throughout the building. Even with the extensive treatment of makeup air and room air in the PBC, a recent study found that the concentrations of common volatile organic compounds and aldehydes appear to rise incrementally as the air passes through the building from the supply to the exhaust. This finding highlights the need to consider the minimization of chemical sources in buildings in combination with the use of advanced air cleaning technologies when seeking to achieve superior IAQ. The goal of this project was to identify potential source materials for indoor chemicals in the PBC. Samples of building materials, including wood paneling (polished and unpolished), drywall, and plastic from a hydroponic drum that was part of the air cleaning system, were collected from the building for testing. All materials were collected from the PBC building and shipped to the Lawrence Berkeley National Laboratory (LBNL) for testing. The materials were pre-conditioned for two different time periods before measuring material and chemical specific emission factors for a range of VOCs and Aldehydes. Of the six materials tested, we found that the highest emitter of formaldehyde was new plywood paneling. Although polish and paint contribute to some VOC emissions, the main influence of the polish was in altering the capacity of the surface to accumulate formaldehyde. Neither the new nor aged polish contributed significantly to formaldehyde emissions. The VOC emission stream (excluding formaldehyde) was composed of up to 18 different chemicals and the total VOC emissions ranged in magnitude from 7 μg/m2/h (old wood with old polish) to >500 μg/m2/h (painted drywall). The formaldehyde emissions from drywall and old wood with either new or old polish were ~ 15 μg/m2/h while the new wood material emitted > 100 μg/m2/h. However, when the projected surface area of each material in the building was considered, the new wood, old wood and painted drywall material all contributed substantially to the indoor formaldehyde loading while the coatings contributed primarily to the VOCs.

This study investigated the hypothesis that increased exposure to polycyclic aromatic hydrocarbons (PAHs) increases breast cancer risk. PAHs are products of incomplete burning of organic matter and are present in cigarette smoke, ambient air, drinking water, and diet. PAHs require metabolic transformation to bind to DNA, causing DNA adducts, which can lead to mutations and are thought to be an important pre-cancer marker. In breast tissue, PAHs appear to be metabolized to their cancer-causing form primarily by the cytochrome P450 enzyme CYP1B1. Because the genotoxic impact of PAH depends on their metabolism, we hypothesized that high CYP1B1 enzyme levels result in increased formation of PAH-DNA adducts in breast tissue, leading to increased development of breast cancer. We have investigated molecular mechanisms of the relationship between PAH exposure, CYP1B1 expression and breast cancer risk in a clinic-based case-control study. We collected histologically normal breast tissue from 56 women (43 cases and 13 controls) undergoing breast surgery and analyzed these specimens for CYP1B1 genotype, PAH-DNA adducts and CYP1B1 gene expression. We did not detect any difference in aromatic DNA adduct levels of cases and controls, only between smokers and non-smokers. CYP1B1 transcript levels were slightly lower in controls than cases, but the difference was not statistically significant. We found no correlation between the levels of CYP1B1 expression and DNA adducts. If CYP1B1 has any role in breast cancer etiology it might be through its metabolism of estrogen rather than its metabolism of PAHs. However, due to the lack of statistical power these results should be interpreted with caution.

Imported drywall installed in U.S. homes is suspected of being a source of odorous and potentially corrosive indoor pollutants. To support an investigation of those building materials by the Consumer Products Safety Commission (CPSC), Lawrence Berkeley National Laboratory (LBNL) measured chemical-specific emission factors for 30 samples of drywall materials. Emission factors are reported for 75 chemicals and 30 different drywall samples encompassing both domestic and imported stock and incorporating natural, synthetic, or mixed gypsum core material. CPSC supplied all drywall materials. First the drywall samples were isolated and conditioned in dedicated chambers, then they were transferred to small chambers where emission testing was performed. Four sampling and analysis methods were utilized to assess (1) volatile organic compounds, (2) low molecular weight carbonyls, (3) volatile sulfur compounds, and (4) reactive sulfur gases. LBNL developed a new method that combines the use of solid phase microextraction (SPME) with small emission chambers to measure the reactive sulfur gases, then extended that technique to measure the full suite of volatile sulfur compounds. The testing procedure and analysis methods are described in detail herein. Emission factors were measured under a single set of controlled environmental conditions. The results are compared graphically for each method and in detailed tables for use in estimating indoor exposure concentrations.

Four unoccupied FEMA temporary housing units (THUs) were studied to assess their indoor emissions of volatile organic compounds including formaldehyde. Measurement of whole-THUVOC and aldehyde emission factors (µg h-1 per m2 of floor area) for each of the four THUs were made at FEMA's Purvis MS staging yard using a mass balance approach. Measurements were made in the morning, and again in the afternoon in each THU. Steady-state indoor formaldehydeconcentrations ranged from 378 µg m-3 (0.31ppm) to 632 µg m-3 (0.52 ppm) in the AM, and from 433 µg m-3 (0.35 ppm) to 926 µg m-3 (0.78 ppm) in the PM. THU air exchange rates ranged from 0.15 h-1 to 0.39 h-1. A total of 45 small (approximately 0.025 m2) samples of surface material, 16 types, were collected directly from the four THUs and shipped to Lawrence Berkeley Laboratory. The material samples were analyzed for VOC and aldehyde emissions in small stainless steel chambers using a standard, accurate mass balance method. Quantification of VOCs was done via gas chromatography – mass spectrometry and low molecular weight aldehydes via high performance liquid chromatography. Material specific emission factors (µg h-1 per m2 of material) were quantified. Approximately 80 unique VOCs were tentatively identified in the THU field samples, of which forty-five were quantified either because of their toxicological significance or because their concentrations were high. Whole-trailer and materialspecific emission factors were calculated for 33 compounds. The THU emission factors and those from their component materials were compared against those measured from other types of housing and the materials used in their construction. Whole THU emission factors for most VOCs were typically similar to those from comparative housing. The three exceptions were exceptionally large emissions of formaldehyde and TMPD-DIB (a common plasticizer in vinyl products), and somewhat elevated for phenol. Of these three compounds, formaldehyde was theonly one with toxicological significance at the observed concentrations. Whole THU formaldehyde emissions ranged from 173 to 266 µg m-2 h-1 in the morning and 257 to 347 µg m-2 h-1 in the afternoon. Median formaldehyde emissions in previously studied site-built and manufactured homes were 31 and 45 µg m-2 h-1, respectively. Only one of the composite wood materials that was tested appeared to exceed the HUD formaldehyde emission standard (430 µg/m2 h-1 for particleboard and 130 µg/m2 h-1 for plywood). The high loading factor (materialsurface area divided by THU volume) of composite wood products in the THUs and the low fresh air exchange relative to the material surface area may be responsible for the excessive concentrations observed for some of the VOCs and formaldehyde.

An assessment of the indoor air quality (IAQ) of the San Francisco Federal Building(SFFB) was conducted on May 12 and 14, 2009 at the request of the General Services Administration (GSA). The purpose of the assessment was for a general screening of IAQ parameters typically indicative of well functioning building systems. One naturally ventilated space and one mechanically ventilated space were studied. In both zones, the levels of indoor air contaminants, including CO2, CO, particulate matter, volatile organic compounds, and aldehydes, were low, relative to reference exposure levels and air quality standards for comparable office buildings. We found slightly elevated levels of volatile organic compounds (VOCs) including two compounds often found in "green" cleaning products. In addition, we found two industrial solvents at levels higher than typically seen in office buildings, but the levels were not sufficient to be of a health concern. The ventilation rates in the two study spaces were high by any standard. Ventilation rates in the building should be further investigated and adjusted to be in line with the building design. Based on our measurements, we conclude that the IAQ is satisfactory in the zone we tested, but IAQ may need to be re-checked after the ventilation rates have been lowered.

The objective of this research project was to improve the basis for estimating environmental tobacco smoke (ETS) exposures in a variety of indoor environments. The research utilized experiments conducted in both laboratory and ‘real-world' buildings to 1) study the transport of ETS species from room to room, 2) examine the viability of using various chemical markers as tracers for ETS, and 3) to evaluate to what extent re-emission of ETS components from indoor surfaces might add to the ETS exposure estimates. A three-room environmental chamber was used to examine multi-zone transport and behavior of ETS and its tracers. One room (simulating a smoker's living room) was extensively conditioned with ETS, while a corridor and a second room (simulating a child's bedroom) remained smoking-free. A series of 5 sets of replicate experiments were conducted under different door opening and flow configurations: sealed, leaky, slightly ajar, wide open, and under forced air-flow conditions. When the doors between the rooms were slightly ajar the particles dispersed into the other rooms, eventually reaching the same concentration. The particle size distribution took the same form in each room, although the total numbers of particles in each room depended on the door configurations. The particle number size distribution moved towards somewhat larger particles as the ETS aged. We also successfully modeled the inter-room transport of ETS particles from first principles – using size fractionated particle emission factors, predicted deposition rates, and thermal temperature gradient driven inter-room flows, This validation improved our understanding of bulk inter-room ETS particle transport. Four chemical tracers were examined: ultraviolet-absorbing particulate matter (UVPM), fluorescent particulate matter (FPM), nicotine and solanesol. Both (UVPM) and (FPM) traced the transport of ETS particles into the non-smoking areas. Nicotine, on the other hand, quickly adsorbed on unconditioned surfaces so that nicotine concentrations in these rooms remained very low, even during smoking episodes. These findings suggest that using nicotine as a tracer of ETS particle concentrations may yield misleading concentration and/or exposure estimates. The results of the solanesol analyses were compromised, apparently by exposure to light during collection (lights in the chambers were always on during the experiments). This may mean that the use of solanesol as a tracer is impractical in 'real-world' conditions. In the final phase of the project we conducted measurements of ETS particles and tracers in three residences occupied by smokers who had joined a smoking cessation program. As a pilot study, its objective was to improve our understanding of how ETS aerosols are transported in a small number of homes (and thus, whether limiting smoking to certain areas has an effect on ETS exposures in other parts of the building). As with the chamber studies, we examined whether measurements of various chemical tracers, such as nicotine, solanesol, FPM and UVPM, could be used to accurately predict ETS concentrations and potential exposures in ‘real-world' settings, as has been suggested by several authors. The ultimate goal of these efforts, and a future larger multiple house study, is to improve the basis for estimating ETS exposures to the general public. Because we only studied three houses no firm conclusions can be developed from our data. However, the results for the ETS tracers are essentially the same as those for the chamber experiments. The use of nicotine was problematic as a marker for ETS exposure. In the smoking areas of the homes, nicotine appeared to be a suitable indicator; however in the non-smoking regions, nicotine behavior was very inconsistent. The other tracers, UVPM and FPM, provided a better basis for estimating ETS exposures in the 'real world'. The use of solanesol was compromised - as it had been in the chamber experiments.

About 50% of viral-induced respiratory illnesses are caused by the human rhinovirus (HRV). Prior research has demonstrated that rhinovirus infections can be transmitted via person-to-person contact and via inhalation of infectious aerosols. Measurements of the concentrations and sizes of bioaerosols are critical for research on building characteristics, aerosol transport, and mitigation measures. To detect airborne HRV, we developed a quantitative reverse transcription-coupled polymerase chain reaction (RT-PCR) assay and verified that this assay detects HRV in nasal lavage samples. A quantitation standard was used to determine the assay detection limit of 5 fg of HRV RNA with a linear range over 10,000-fold. This assay was used to quantify the size distribution of an artificially-produced HRV aerosol captured with an Andersen six-stage cascade impactor. In future studies, we hope to use the methods developed here to characterize the size distribution of naturally occurring viral-aerosols.

The purpose of the Personal Environmental Risk Factor Study (PERFS) pilot project was to develop methodologies and a questionnaire for a future population-based case-control study to investigate the role of selected environmental exposures in breast cancer development. Identification of etiologically relevant exposures during a period of potential vulnerability proximate to disease onset offers the possibility of clinical disease prevention even when disease initiation may have already occurred many years earlier. Certain personal environmental agents or combinations of agents may influence disease promotion. Therefore, this pilot study focused on exposures that occurred during the ten-year period prior to diagnosis for cases and the last ten years for controls, rather than more historic exposures. For this pilot study, we used a community-based research approach. In our collaborative efforts, community members participated with academic researchers in all phases of the research, including research question identification, study design, development of research tools, development of the human subjects protocol, and report writing. Community member inclusion was based upon the concept that community participation could improve the relevance of scientific studies and ultimate success of the research by encouraging an ongoing dialogue between community members and academic representatives. Early activities of this project focused on the collection of input from the community regarding the possible role of environmental factors in the incidence of breast cancer in Marin County. The intent was to inform the scientists of community concerns, enhance the research team's understanding of the community being studied, and provide interested community members with a better understanding of the strengths and weaknesses of traditional research methods through active participation in the research process. This pilot study identified specific testable hypotheses through review of the literature and consultation with relevant experts and the affected community. Initially, the study was to focus on modifiable personal environmental exposures that are associated with breast tumor promotion and higher socioeconomic status (SES). However, little information was available in the scientific literature regarding the putative mechanism by which some of the suspected environmental factors may act (i.e., initiator vs. promoter). Likewise, little is known about the distribution of personal environmental risk factors by socioeconomic status. Therefore, tumor promotion involvement and association with SES were not very useful as selection criteria, and selection of topics was based primarily on published scientific findings of human studies and community input. This study was approved by the Institutional Review Boards at the University of California at San Francisco (Committee on Human Research) and at the University of California at Berkeley (Committee for the Protection of Human Subjects).

A study of the relationship between outside air ventilation rate and concentrations of volatile organic compounds (VOCs) generated indoors was conducted in a call center office building. The building, with two floors and a total floor area of 4600 m2, is located in the San Francisco Bay Area, CA. Ventilation rates were manipulated with the building's four air handling units (AHUs). VOC and CO2 concentrations in the AHU returns were measured on 7 days during a 13-week period. VOC emission factors were determined for individual zones on days when they were operating at near steady-state conditions. The emission factor data were subjected to principal component (PC) analysis to identify groups of co-varying compounds. Potential sources of the PC vectors were ascribed based on information from the literature. The per occupant CO2 generation rates were 0.0068–0.0092 l s−1. The per occupant isoprene generation rates of 0.2–0.3 mg h−1 were consistent with the value predicted by mass balance from breath concentration and exhalation rate. The relationships between indoor minus outdoor VOC concentrations and ventilation rate were qualitatively examined for eight VOCs. Of these, acetaldehyde and hexanal, which likely were associated with material sources, and decamethylcyclopentasiloxane, associated with personal care products, exhibited general trends of higher concentrations at lower ventilation rates. For other compounds, a clear inverse relationship between VOC concentrations and ventilation was not observed. The net concentration of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate isomers, examples of low-volatility compounds, changed very little with ventilation likely due to sorption and re-emission effects. These results illustrate that the efficacy of ventilation for controlling VOC concentrations can vary considerably depending upon the operation of the building, the pollutant sources and the physical and chemical processes affecting the pollutants. Thus, source control measures, in addition to adequate ventilation, are required to limit concentrations of VOCs in office buildings.

7H-Benzo[c]fluorene (B[c]F) has been known for a long time as a component of complex mixtures such as coal tar or cigarette smoke. B[c]F has been identified recently as a potent lung tumorigen and a major DNA adduct-forming component of coal tar. We have investigated if human cells have the ability to form B[c]F:DNA adducts as detected in lungs of mice treated with B[c]F. MCF7 (human breast cancer), HepG2 (hepatoma) and Caco-2 (colon adenocarcinoma) cells were treated with increasing concentrations (0.2 — 10 *g/ml) of B[c]F for 20 hours. Adduct formation was evaluated using 32P-postlabeling. A dose response in DNA adduct formation was detected in all three cell lines. In MCF7 and HepG2 cells, two adducts were detected, one of them corresponded to an adduct observed in the lungs of mice treated with B[c]F. This adduct is derived from 3-hydroxy B[c]F while the second, slower migrating adduct, appears to be unique to human cells. In contrast, Caco-2 cells formed at least four adducts. Two of the three most predominant adducts correspond to the two adducts observed in MCF7 and HepG2 cells while the additional predominate and a minor adduct are derived from 3,4-dihydrodiol B[c]F. The adducts derived from 3,4-dihydrodiol B[c]F are similar to those observed in mouse lung and skin. The detection of B[c]F:DNA adducts clearly demonstrates that human cells have the capacity to metabolically activate B[c]F to derivatives that covalently modify DNA. Similarities in the types of B[c]F:DNA adducts detected also demonstrates that B[c]F activation is similar in both human cells and mouse tissue.

About 50% of viral-induced respiratory illnesses are caused by the human rhinovirus (HRV). Measurements of the concentrations and sizes of bioaerosols are critical for research on building characteristics, aerosol transport, and mitigation measures. We developed a quantitative reverse transcription-coupled polymerase chain reaction (RT-PCR) assay for HRV and verified that this assay detects HRV in nasal lavage samples. A quantitation standard was used to determine a detection limit of 5 fg of HRV RNA with a linear range over 1000-fold. To measure the size distribution of HRV aerosols, volunteers with a head cold spent two hours in a ventilated research chamber. Airborne particles from the chamber were collected using an Andersen Six-Stage Cascade Impactor. Each stage of the impactor was analyzed by quantitative RT-PCR for HRV. For the first two volunteers with confirmed HRV infection, but with mild symptoms, we were unable to detect HRV on any stage of the impactor.

The human colon adenocarcinoma cell line, Caco-2, was used to study intestinal uptake of benzo(a)pyrene (BaP). BaP permeation was measured across Caco-2 monolayers grown on permeable supports that separate two chambers representing the intestinal lumen and the bloodstream. At high BaP concentration (10 μM) BaP permeation of the cell layer occurred at a linear rate. At lower and physiologically more relevant BaP concentrations (0.2 and 1 μM) permeation showed a more complex pattern with initial linear rate, then accelerated and finally reduced permeation. From the earliest sampling on (0.5 h) BaP permeation of the cell layer was accompanied by extensive metabolism to water soluble conjugates not extracted by organics. With 0.2 μM BaP about half the 3Hlabeled material appearing in the basolateral chamber consisted of BaP conjugates, and of the 3H-material extracted with organic solvents about half consisted of BaP metabolites. In addition we found that Caco-2 cells preferentially released metabolites into the apical chamber representing the intestinal lumen. We conclude that the intestinal epithelium is an important barrier that limits systemic availability of ingested BaP by presystemic detoxification and outwardly directed transport. We also conclude that the Caco-2 cell system is a useful in vitro model to predict systemic availability of xenobiotics in general.